move or just leave transform attr from Group to the inner Path Elems (close #86)

plugins/moveGroupAttrsToElems.js

@@ -0,0 +1,46 @@
+'use strict';
+
+var pathElems = require('./_collections.js').pathElems;
+
+/**
+ * Move group attrs to the content elements.
+ *
+ * @example
+ * <g transform="scale(2)">
+ *     <path transform="rotate(45)" d="M0,0 L10,20"/>
+ *     <path transform="translate(10, 20)" d="M0,10 L20,30"/>
+ * </g>
+ *                          ⬇
+ * <g>
+ *     <path transform="scale(2) rotate(45)" d="M0,0 L10,20"/>
+ *     <path transform="scale(2) translate(10, 20)" d="M0,10 L20,30"/>
+ * </g>
+ *
+ * @param {Object} item current iteration item
+ * @return {Boolean} if false, item will be filtered out
+ *
+ * @author Kir Belevich
+ */
+exports.moveGroupAttrsToElems = function(item) {
+
+    // move group transform attr to content's pathElems
+    if (
+        item.isElem('g') &&
+        item.hasAttr('transform') &&
+        !item.isEmpty() &&
+        item.content.every(function(inner) {
+            return inner.isElem(pathElems);
+        })
+    ) {
+        item.content.forEach(function(inner) {
+            if (inner.hasAttr('transform')) {
+                inner.attr('transform').value = item.attr('transform').value + ' ' + inner.attr('transform').value;
+            } else {
+                inner.addAttr(item.attr('transform'));
+            }
+        });
+
+        item.removeAttr('transform');
+    }
+
+};